This invention relates generally to power-driven position adjusters for motor-vehicle seats, and more specifically it relates to an adjuster of the type having a servomotor for adjusting the position of the seat, a potentiometer coupled to the servomotor via a reduction gear to generate a repeatable signal corresponding to the adjusted position of the seat, and an electronic data processing and storing device, such as a microprocessor, controlled by the potentiometer and connected for controlling the servomotor.
For adjusting the position of a motor-driven adjustable seat, it has been suggested to couple the servomotor to a potentiometer which supplies the measured partial voltage corresponding to the adjusted position of the seat to the memory of a data processing device such as for example a microprocessor. In this manner it is possible to reset exactly and automatically the initially selected position irrespective of its subsequent changes provided that the measured value pertaining to the initially set position which in this case is represented by a certain partial voltage on the potentiometer, is stored in the data processing device. Due to the fact, however, that the seat is adjustable in a predetermined range, the traverse of which normally requires a large number of rotations of the driving shaft of the motor whereas the path of the movable part of the potentiometer is relatively small, it is necessary to reduce the number of rotations of the driving shaft to match the rotation of the potentiometer. For this purpose a reduction gear arranged between the potentiometer and the driving shaft is employed. Conventional reduction gears used for this purpose require a considerable installation space and in addition are mounted on brackets or the like connected to the seat. Moreover, in many cases it is necessary to provide respectively both the reduction gears and the potentiometer with protective housings in order to separate the two units from detrimental effects of the environment.